Method of making matrix composites

Abstract

Matrix composites and especially metal matrix composites are formed by coating a foam with a metal or ceramic to form a continuous structure from which the foam material is removed by pyrolysis. If this structure is composed of a metal it is subjected to treatment to transform the metal to a ceramic and the resulting ceramic structure is then filled with another material such as a matrix metal. The product is then compacted and heat treated if desired. The coating of the foam and the filling of the porous ceramic structure are effected preferably by low temperature arc vapor deposition.

I claim: 
     
       1. A method of making a matrix composite which comprises the steps of: (a) coating interstitial and external walls of a synthetic resin foax: material with a first substance resistant to heat so as to form a body with a continuous network from said first substance;   (b) pyrolyzing said synthetic resin foam material of said body to substantially completely remove said synthetic resin material to leave a porous structure substantially free from interfaces between strands of said structure and constituted by said network;   (c) depositing a second substance in pores of said structure to substantially fill the same and form a matrix phase in which said porous structure is embedded; and   (d) compacting the structure filled with the matrix phase to form the matrix composite.   
     
     
       2. The method defined in claim 1 wherein a barrier coating is deposited on said porous structure subsequent to step (b) and prior to step (c) and consists of a material forming a thermally stable interfacial bond, said thermal structure and said second substance. 
     
     
       3. The method defined in claim 2 wherein said barrier coating consists of at least one substance selected from the group which consists of nickel, chromium, chromium nitride, chromium carbide, titanium oxide, titanium nitride, titanium carbide and aluminum oxide. 
     
     
       4. The method defined in claim 2 wherein said barrier coating is applied to said porous structure by striking an arc between electrodes across which a voltage of substantially 20 to 150 volts is applied, in an evacuated chamber, with an arc current of substantially 30 to 150 amperes to produce a vapor of a material of said barrier coating and deposit said material of said barrier coating on said substrate. 
     
     
       5. The method defined in claim 1 wherein said interstitial and external walls of said synthetic resin foam material are coated with said first substance by striking an arc between electrodes across which a voltage of substantially 20 to 150 volts is applied, in an evacuated chamber, with an arc current of substantially 30 to 150 amperes to produce a vapor of said first substance in said chamber and deposit said first substance from said vapor onto and into said foam material in said chamber, at least one of said electrode's being constituted with at least one component of said first substance 
     
     
       6. The method defined in claim 5 wherein said component is a metal or silicon or boron. 
     
     
       7. The method defined in claim 6 wherein said component is selected from the group which consists of aluminum, silicon, zirconium, titanium, chromium, tantalum, molybdenum, boron and niobium and mixtures and alloys thereof. 
     
     
       8. The method defined in claim 6, further comprising the step of treating said structure to transform said metal substantially throughout the thickness thereof to at least one ceramic compound whereby said structure is constituted as a continuous ceramic structure. 
     
     
       9. The method defined in claim 8 wherein said ceramic compound is an oxide, carbide or nitride. 
     
     
       10. The method defined in claim 8 wherein said structure is treated to transform said metal by anodization of said structure. 
     
     
       11. The method defined in claim 5 wherein said first substance deposited on said synthetic resin foam material is at least one ceramic compound whereby said structure is constituted as a continuous ceramic structure. 
     
     
       12. The method defined in claim 11 wherein said first substance is at least one oxide, nitride or carbide of at least one metal selected from the group which consists of aluminum, zirconium, titanium, chromium, tantalum, molybdenum, and niobium and mixtures and alloys thereof, or silicon or boron. 
     
     
       13. The method defined in claim 1 wherein said second substance is a metal forming said matrix phase or silicon or boron. 
     
     
       14. The method defined in claim 13 wherein said metal is selected from the group which consists of silver, copper, nickel, cobalt, vanadium, a rare-earth element, a platinum-group metal, aluminum, zirconium, titanium, chromium, tantalum, molybdenum, and niobium and mixtures and alloys thereof. 
     
     
       15. The method defined in claim 1 wherein said second substance is deposited in said pores of said structure to at least partially fill the same and form said matrix phase in which said porous structure is embedded by striking an arc between electrodes across which a voltage of substantially 20 to 150 volts is applied, in an evacuated chamber, with an arc current of substantially 30 to 150 amperes to produce a vapor of said second substance in said chamber and deposit said second substance from said vapor onto and into said structure in said chamber, at least one of said electrodes being constituted with at least one component of said second substance. 
     
     
       16. The method defined in claim 1 wherein the structure filled with the matrix phase is compacted to form the matrix composite at least in part by pressing the structure filled with the matrix phase. 
     
     
       17. The method defined in claim 1, wherein the structure filled with the matrix phase is compacted to form the matrix composite at least in-part by heat-treating the structure filled with the matrix phase, thereby densifying same. 
     
     
       18. The method defined in claim 1 wherein the matrix composite is rolled to a desired thickness following compaction thereof.